AllowChar
void AllowChar(uint32 character);
fSizeTextControl->TextView()->AllowChar(i);
AllowChar(c);
AllowChar('-');
AllowChar('.');
fRedText->TextView()->AllowChar(i);
fGreenText->TextView()->AllowChar(i);
fBlueText->TextView()->AllowChar(i);
textView->AllowChar('0' + num);
tv->AllowChar(i);
tv->AllowChar(B_BACKSPACE);
tv->AllowChar('.');
fScaling->TextView()->AllowChar('0' + num);
fPageNumber->TextView()->AllowChar('0' + num);